In recreational vehicles, and in other applications where space is at a premium, it is advantageous and well-known in the prior art to provide a multi-purpose seat which may be manipulated to form a generally horizontal cushioned surface which may be used as a bed.
U.S. Pat. No. 4,131,960 discloses a seat-bed design having a seat portion and a back portion supported on a linkage which allows the seat portion and back portion to be articulated between a seat position and a bed position. In the seat position, the seat portion is generally horizontal and the back portion extends generally vertically upward from the rear edge of the seat portion to form a conventional seat. When articulated to the bed position, the seat portion and the back portion lie adjacent each other in the same horizontal plane.
The disadvantage of this arrangement is that the length of the seat-bed in the bed position is the length of the seat portion plus the height of the back portion. This produces a rather short bed which is suitable for a child, but uncomfortably short for an adult.